Investigate using the message index in the ChainStore

[fridrik01]

See Epic: Message Index #10536 for background

In PR #10452 we introduced a Message Index to Lotus which is backed by a sqlite backend and allows us to speed up certain calls like StateSearchMessage.

We may be able to use this index in the ChainStore, but it's unclear. We should investigate (see #10452 (comment) for context).

[maciejwitowski]

Lowering the priority based on info from @fridrik01

It turns out that that task was more an "investigation" rather than actually refactor since it was not clear how much that change will improve performance

[Stebalien]

Benchmarking determined that this isn't required.